scholarly journals Evidence for Secular Evolution in Late-Type Spirals

1996 ◽  
Vol 457 (2) ◽  
Author(s):  
Stéphane Courteau ◽  
Roelof S. de Jong ◽  
Adrick H. Broeils
Keyword(s):  
Late Type ◽  
Secular Evolution

scholarly journals The imprint of arms and bars on rotation curves: in-plane and off-plane

2020 ◽  
Vol 496 (2) ◽  
pp. 1845-1856
Author(s):  
Luis A Martinez-Medina ◽  
Barbara Pichardo ◽  
Antonio Peimbert
Keyword(s):  
Spiral Galaxy ◽  
Pitch Angle ◽  
Local Minima ◽  
Late Type ◽  
Rotation Curves ◽  
Spiral Arms ◽  
Stellar Disc ◽  
Secular Evolution ◽  
Galaxy Model ◽  
Characteristic Features

ABSTRACT Within rotation curves (RCs) is encoded the kinematical state of the stellar disc as well as information about the dynamical mechanisms driving the secular evolution of galaxies. To explain the characteristic features of RCs which arise by the influence of spiral patterns and bar, we study the kinematics of the stellar disc in a set of spiral galaxy models specifically tailored for this purpose. We find that, for our models, the induced non-circular motions are more prominent for spirals with larger pitch angle, the ones typical in late-type galaxies. Moreover, inside corotation, stars rotate slower along the spiral arms than along the interarm, which translates into a local minima or maxima in the RC, respectively. We also see, from off-plane RC, that the rotation is faster for stars that at observed closer to the plane, and diminishes as one looks farther off plane; this trend is more noticeable in our Sa galaxy model than our Sc galaxy model. Additionally, in a previous work we found that the diagonal ridges in the Vϕ–R plane, revealed through the GaiaDR2, have a resonant origin due to the spiral arms and bar and that these ridges project themselves as wiggles in the RC; here, we further notice that the development of these ridges, and the development of high orbital eccentricities in the stellar disc are the same. Hence, we conclude that, the following explanations of bumps and wiggles in RCs are equivalent: they are manifestations of diagonal ridges in the Vϕ–R plane, or of the rearrangement of the orbital eccentricities in the stellar disc.

scholarly journals Effects of secular evolution on the star formation history of galaxies

2012 ◽  
Vol 10 (H16) ◽  
pp. 367-367
Author(s):  
M. Fernández Lorenzo ◽  
J. Sulentic ◽  
L. Verdes–Montenegro ◽  
M. Argudo-Fernández ◽  
J. E. Ruiz ◽  
...  
Keyword(s):  
Star Formation ◽  
Morphological Type ◽  
Stellar Mass ◽  
Star Formation History ◽  
Late Type ◽  
Absolute Deviation ◽  
Secular Evolution ◽  
Isolated Galaxies ◽  
Formation History ◽  
Close Pairs

AbstractWe report the study performed as part of the AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies; http://www.amiga.iaa.es) project, focused on the SDSS (g-r) colors of the sample. Assuming that color is an indicator of star formation history, this work better records the signature of passive star formation via pure secular evolution. Median values for each morphological type in AMIGA were compared with equivalent measures for galaxies in denser environments. We found a tendency for AMIGA spiral galaxies to be redder than galaxies in close pairs, but no clear difference when we compare with galaxies in other (e.g. group) environments. The (g-r) color of isolated galaxies presents a Gaussian distribution, as indicative of pure secular evolution, and a smaller median absolute deviation (almost half) compared to both wide and close pairs. This redder color and lower color dispersion of AMIGA spirals compared with close pairs is likely due to a more passive star formation in very isolated galaxies. In Fig. 1, we represent the size versus stellar mass for early and late–type galaxies of our sample, compared with the local relations of Shen et al. (2003). The late–type isolated galaxies are ~1.2 times larger or have less stellar mass than local spirals in other environments. The latter would be in agreement with the passive star formation found in the previous part.We acknowledge Grant AYA2011-30491-C02-01, P08-FQM-4205 and TIC-114.

scholarly journals Angular Momentum Loss and Transfer in Close Binaries: Effects on a Human Time-Scale?

1998 ◽  
Vol 11 (1) ◽  
pp. 353-353
Author(s):  
C. Maceroni
Keyword(s):  
Angular Momentum ◽  
Orbital Period ◽  
Dynamical Evolution ◽  
Cumulative Effect ◽  
Great Accuracy ◽  
Close Binaries ◽  
Late Type ◽  
Secular Evolution ◽  
Evolutionary Changes ◽  
Orbital Periods

The orbital periods of binaries are known to great accuracy, their changes produce an easily detectable cumulative effect and many systems have been observed for more than a century. In tidually locked late-type binaries the orbital period changes are often related to structural or evolutionary changes. The study of the orbital period secular evolution can therefore provide information on phenomena taking place on timescales very short when compared to the typical stellar evolutionary scales, but still much longer thant the human lifetime. This paper focuses on the dynamical evolution due to magnetic braking in late-type close binaries and on the detectability of angular momentum transfer among the stellar layers.

A Search for Dyson Spheres around Late-Type Stars in the Solar Neighborhood II

1997 ◽  
Vol 161 ◽  
pp. 707-709 ◽  
Author(s):  
Jun Jugaku ◽  
Shiro Nishimura
Keyword(s):  
Solar Neighborhood ◽  
The Sun ◽  
Late Type ◽  
Solar Type

AbstractWe continued our search for partial (incomplete) Dyson spheres associated with 50 solar-type stars (spectral classes F, G, and K) within 25 pc of the Sun. No candidate objects were found.

The12CO(1—0) to H2conversion factor in normal late-type galaxies

2002 ◽  
Vol 4 ◽  
pp. 393-393
Author(s):  
A. Boselli ◽  
J. Lequeux ◽  
G. Gavazzi
Keyword(s):  
Late Type

Faint Sources in theEUVESurvey: Identification of White Dwarfs, Active Late‐Type Stars, and Galactic Nuclei

1997 ◽  
Vol 486 (1) ◽  
pp. 179-196 ◽  
Author(s):  
Elisha Polomski ◽  
Stephane Vennes ◽  
John R. Thorstensen ◽  
Mihalis Mathioudakis ◽  
Emilio E. Falco
Keyword(s):  
White Dwarfs ◽  
Galactic Nuclei ◽  
Late Type

X‐Ray Spectroscopy of Rapidly Rotating, Late‐Type Dwarf Stars

1999 ◽  
Vol 512 (2) ◽  
pp. 874-891 ◽  
Author(s):  
K. P. Singh ◽  
S. A. Drake ◽  
E. V. Gotthelf ◽  
N. E. White
Keyword(s):  
Late Type ◽  
Dwarf Stars ◽  
X Ray

scholarly journals SDSS-IV MaNGA: radial gradients in stellar population properties of early-type and late-type galaxies

2021 ◽  
Vol 502 (4) ◽  
pp. 5508-5527
Author(s):  
Taniya Parikh ◽  
Daniel Thomas ◽  
Claudia Maraston ◽  
Kyle B Westfall ◽  
Brett H Andrews ◽  
...  
Keyword(s):  
Stellar Population ◽  
Mass Range ◽  
Mass Relation ◽  
Individual Element ◽  
Late Type ◽  
Element Abundances ◽  
Entire Mass Range ◽  
Strong Gradient ◽  
Star Formation Histories ◽  
Absorption Features

ABSTRACT We derive ages, metallicities, and individual element abundances of early- and late-type galaxies (ETGs and LTGs) out to 1.5 Re. We study a large sample of 1900 galaxies spanning 8.6–11.3 log M/M⊙ in stellar mass, through key absorption features in stacked spectra from the SDSS-IV/MaNGA survey. We use mock galaxy spectra with extended star formation histories to validate our method for LTGs and use corrections to convert the derived ages into luminosity- and mass-weighted quantities. We find flat age and negative metallicity gradients for ETGs and negative age and negative metallicity gradients for LTGs. Age gradients in LTGs steepen with increasing galaxy mass, from −0.05 ± 0.11 log Gyr/Re for the lowest mass galaxies to −0.82 ± 0.08 log Gyr/Re for the highest mass ones. This strong gradient–mass relation has a slope of −0.70 ± 0.18. Comparing local age and metallicity gradients with the velocity dispersion σ within galaxies against the global relation with σ shows that internal processes regulate metallicity in ETGs but not age, and vice versa for LTGs. We further find that metallicity gradients with respect to local σ show a much stronger dependence on galaxy mass than radial metallicity gradients. Both galaxy types display flat [C/Fe] and [Mg/Fe], and negative [Na/Fe] gradients, whereas only LTGs display gradients in [Ca/Fe] and [Ti/Fe]. ETGs have increasingly steep [Na/Fe] gradients with local σ reaching 6.50 ± 0.78 dex/log km s−1 for the highest masses. [Na/Fe] ratios are correlated with metallicity for both galaxy types across the entire mass range in our sample, providing support for metallicity-dependent supernova yields.

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